Some web processing machines, for example article wrapping machines of the type disclosed in U.S. Pat. Nos. 2,918,769; 3,045,405 and 4,004,400, exert a pulling force on the web to advance the web through the processing machine. However, it is frequently desirable to assist feeding of the web material to the processing machine at a rate correlated with the rate of advance of the web by the processing machine. In U.S. Pat. No. 2,918,769 there is disclosed a web feed apparatus for feeding a plurality of webs to a multi-web wrapping machine in which the webs, after being longitudinally folded, are passed over a continuously rotating feed roller. When the web processing machine pulls on the web, the web is drawn against the continuously rotating feed roller which then operates to advance the same until the tension on the exiting web is reduced to a sufficiently low value that the roller merely slips relative to the web. In addition, provision was made for driving the web supply roll to overcome the inertia problems in starting and stopping unwinding rotation of the supply roll and to maintain a storage loop of web material under low tension. As disclosed more fully in that patent, the web supply roll was supported on a pair of drive rollers that were connected through a clutch mechanism to a continuously rotating drive shaft and the clutch mechanism was operated by a mechanism responsive to the tension in the web exiting from the roll to start and stop the drive rollers to maintain a slack loop of web material between the supply roll and the web feed roller. The web feed apparatus disclosed in U.S. Pat. No. 2,918,769 worked well with some web material such as coated paper and the like. However, difficulties were encountered with relatively stretchable thin and plastic films such as polyethylene, polypropylene, etc. It was found that the plastic film material would sometimes tend to adhere to the continuously rotating feed roller and wrap around the roller causing a jam-up in the machine. Attempts to overcome this problem by use of a clutch operated in timed relation with the advance of the wrapping machine to start and stop the feed rollers, were not successful.